Let me help with some key concepts.

Supply and demand doesn't work in real estate. Why? Real estate has three fundamental 'values'.

1. Use-Value: how people use the building.

2. Exchange-Value: how much a building is worth when sold.

3. Capital-Value: how much a building stores wealth as an asset.

In late stage capitalism and globalism, societies do not create 'capital', rather they rob capital from 'undeveloped' economies and store them in capitalist cities like London, New York, and San Francisco. This is called 'Uneven Development' and is a capitalist form of colonialism. Henri Lefebvre's theory was that capitalism would have failed after the industrial revolution if not for storing capital in cities. This creates a global center of capital, and the global periphery.

Rent is so high because the Capital-Value of real estate is higher than its Use-Value.

You touched on another concept and that is a debt based economy. I think that we are seeing the capitalist system as Lefebvre knew it break down and a new 'debt' based economy emerge. In this system Capital-Value of real estate would break down and the Exchange-Value in the form of debt would dominate. This also does not help the renter as their building simply goes from being capital to debt. The fundamental problem is Use-Value is under valued, while Exchange and Capital value is over valued. The problem is global capitalism.